Star-forming region RCW 108 in Ara

Eso_eso9925a_500

eso_eso9925a April 30th, 1999

Credit: ESO

RCW 108 is a molecular cloud that is in the process of being destroyed by intense ultraviolet radiation from heavy and hot stars in the nearby stellar cluster NGC 6193, seen to the left in the photo. A series of images were obtained with the Wide Field Imager (WFI) of areas in the Milky Way band, including some in which interstellar nebulae of gas and dust are seen. Each frame records 8184 x 8196, or over 67 million, pixels in a sky field of 32 x 32 arcmin 2. The photo shows the RCW 108 complex of bright and dark nebulae in the southern association Ara OB1, a star-forming region in the constellation Ara (the Altar), deep in the southern sky. The resolution in this image has been degraded by reducing the number of pixels in one direction from about 8000 to 3000 in the "High-Resolution version", in order to make the image transportable over the web without incurring completely unacceptable transfer times. Still, it is very large, even in the highly compressed jpeg format, reflecting the great amount of details visible. This colour picture is a composite made from 12 separate images, obtained with the WFI on 27 March 1999. The blue component corresponds to the B filter, the green to the V filter, and the red to the H-alpha filter. The images in each filter are the composite of 4 individual frames obtained with the telescope pointing at slightly different positions on the sky, so that the parts of the sky falling in the gaps between the 8 individual 2k x 4k CCDs in any given frame are recorded on the others. The monochromatic images are then produced by superimposing the individual frames, correcting for the telescope offsets ; this ensures that the complete field is well covered. This procedure is not simple, as the observing conditions may change slightly from exposure to exposure, resulting in small differences. Finally, the combined images in each filter are aligned and colour-coded to produce the colour picture. For the processing of this large photo (8k x 8k; 256 Mbytes), a minimum of contrast correction was made and very faint lines may still be perceived in some places where the individual frames were joined. It may also be noted that there is a slight misalignment of the individual colours in stellar images at the extreme corners of the large field. This is due to the effect of differential atmospheric refraction, i.e. light rays of different colours are bent differently in air. The exposure time was 300 sec for each frame in H-alpha, and 60 sec in B and V. East is to the left and North to the top.

Image Source: https://www.eso.org/public/images/eso9925a/

Curator: European Southern Observatory, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
NGC 6188 NGC 6193 RCW 108
Subject - Milky Way
Star » Grouping » Cluster » Open
Nebula » Appearance » Dark » Molecular Cloud
Eso_eso9925a_128
 

Position Details

Position (ICRS)
RA = 16h 40m 0.1s
DEC = -48° 51’ 44.8”
Orientation
North is 0.2° CW
Field of View
33.0 x 31.6 arcminutes
Constellation
Ara

Color Mapping

  Telescope Spectral Band Wavelength
Arrow_left_blue MPG/ESO 2.2-metre telescope (WFI) Optical (B) -
Arrow_left_green MPG/ESO 2.2-metre telescope (WFI) Optical (V) -
Arrow_left_red MPG/ESO 2.2-metre telescope (WFI) Optical (H-alpha) -
Eso_eso9925a_1280
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ID
eso9925a
Subject Category
B.3.6.4.1   B.4.2.3.1  
Subject Name
NGC 6188, NGC 6193, RCW 108
Credits
ESO
Lightyears
Redshift
Reference Url
https://www.eso.org/public/images/eso9925a/
Type
Observation
Image Quality
Distance Notes
Facility
MPG/ESO 2.2-metre telescope, MPG/ESO 2.2-metre telescope, MPG/ESO 2.2-metre telescope
Instrument
WFI, WFI, WFI
Color Assignment
Blue, Green, Red
Band
Optical, Optical, Optical
Bandpass
B, V, H-alpha
Central Wavelength
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
250.000359, -48.862457
Reference Dimension
4000.0, 3823.0
Reference Pixel
3107.71706458, 1647.80185264
Scale
-0.0001376836, 0.0001376836
Rotation
-0.15414844030
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
European Southern Observatory
URL
http://www.eso.org/
Name
Email
Telephone
Address
Karl-Schwarzschild-Strasse 2
City
Garching bei München
State/Province
Postal Code
D-85748
Country
Germany
Rights
Creative Commons Attribution 4.0 International License
Publisher
European Southern Observatory
Publisher ID
eso
Resource ID
eso9925a
Metadata Date
2011-03-16T15:46:06+01:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

 

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There is no distance meta data in this image.